A substantial proportion of caskets are contained within crypts in above ground mausoleums. It has been found that the metal casket is prone to deterioration through corrosion by organic acids contained within the casket, as well as by oxidative corrosion. The oxidation of formaldehyde used as the embalming fluid generates formic acid, and the decomposition of the human remains also generates other organic acids which will attack and corrode the metal casket, resulting in the destruction of the casket and leakage of acidic components. The leakage of acid from the casket can stain discolor and damage the marble crypt.
In addition, the putrefication of the human remains in the casket due to microbial growth can cause undesirable odors in the crypt and mausoleum.
Attempts have been made in the past to prevent the corrosion of metal caskets by the application of various types of coatings to the interior casket surface. Asphalt coatings have been commonly used to coat caskets, but the asphalt coating is easily undermined by the organic acids and the coating does little to protect the metal casket from acidic corrosion.
In the past, amine salts have also been placed in caskets and over a period of time the salts sublime or vaporize. The vapors condense on the walls of the casket to form a protective coating in an attempt to halt corrosion. However, the amine salts have not been satisfactory in combating acidic corrosion caused by organic acids.
Polyurethane foam has also been used as a coating on the interior of metal caskets, but as in the case of asphalt coatings, the polyurethane foam does not inhibit the corrosive action of the acid vapors on the uncoated areas.
Furthermore, none of the conventional casket coatings, as used in the past, have inhibited bacterial growth in the casket.